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This invention relates generally to control systems for appliances, and more particularly, to a control system for a refrigerator.
Known household appliances are available in various platforms having different structural features, operational features, and controls. For example, known refrigerator platforms include side-by-side single and double fresh food and freezer compartments, and vertically oriented fresh food and freezer compartments including top mounted freezer compartments, and bottom mounted freezer compartments. Conventionally, a different control system is used in each refrigerator platform. For example, a control system for a side-by-side refrigerator typically controls the freezer temperature by controlling operation of a mullion damper located between the fresh food compartment and the freezer compartment, a fresh food fan and a variable or multi-speed fan-speed evaporator fan. Top mount refrigerators and bottom mount refrigerators however, are available with and without a mullion damper, the absence or presence of which consequently affects the refrigerator controls. Other major appliances, including dishwashers, washing machines, dryers and ranges, are available in various platforms and employ different control schemes.
Known electronically controlled appliances typically employ a dedicated connection between a controller and a plurality of peripheral devices, including but not limited to sensors to monitor various operating conditions of the appliance. Typically, analog signals are transmitted between the sensors and the controller. These analog signals, however, are vulnerable to electrical interference, which can compromise performance of the appliance. To reduce electrical interference, additional electronic circuitry may be employed, but only at increased complexity and cost of the control scheme. Further, ever-expanding appliance features entail relatively sophisticated control schemes and many electrical connections to place all the peripheral devices in communication with the controller. A large number of electrical connections not only increases assembly costs, but presents a possible defect in manufacturing or possibility of failure in use.
In an exemplary embodiment, a control system for an appliance utilizing a plurality of peripheral devices includes a controller and a communications bus coupled to the plurality of peripheral devices and to the controller. The controller is configured to receive data from the peripheral devices over the communications bus and transmit control operations to the peripheral devices based on the data received. The communications bus reduces overall wiring requirements due to elimination or reduction of power wiring of the peripheral devices, thereby increasing appliance reliability and safety performance. Distributed displays and human machine interfaces are also facilitated, and model differentiation is obtainable with late point identification by a population of bus connections with a sensor, display, interface, or a blank. Further, use of a digital low voltage bus system increases data reliability in the presence of electrical noise, thus improving electromagnetic compatibility of an appliance.
In one aspect, the communications bus is an asynchronous serial communications bus, and a data collision detection system prevents miscommunication between the controller and the peripheral devices. The controller includes a diagnostic communications port for requesting data available on the bus from the peripheral devices. The peripheral devices are each configured to be at least one of a master and a slave to send or receive a command packet over the bus to execute control functions. The peripheral devices include sensors, circuit boards, displays, or subsystems of the appliance, such as, for example, a refrigerator icemaker or dispensing system.
A flexible control scheme is therefore provided for reliable controlling various appliance platforms with a single control scheme.